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From Thomas Mueller <muel...@adobe.com>
Subject Re: Internal content in Oak
Date Thu, 19 Jul 2012 07:21:26 GMT

I believe we have quite different views about what the architecture should
look like and what the goals of the separation between the layers are. I
understand the view people have changes as we implement things, but could
we discuss the architecture and problems we found in the next meeting? I
think that's more efficient than trying to discuss it by email.

> Š oak-http are the
> only complex direct Java clients of the Oak API

I thought Oak HTTP basically _is_ (very closely matches) the Oak API.

> I instinctively prefer to keep the Oak API

> as tight and simple as possible

I agree the Oak API should be simple, but if needed an API can be simple
even if the functionality below the API is rich.

On the other hand, we seem to have features (for example the transient
space) that were originally planned for the client now implemented in Oak
Core or even Oak MK (branch / merge). We should really discuss this.



On 7/18/12 4:17 PM, "Jukka Zitting" <jukka.zitting@gmail.com> wrote:

>On Tue, Jul 17, 2012 at 1:01 PM, Angela Schreiber <anchela@adobe.com>
>> not sure if it wise to expose such invisible content as "regular items"
>> on the oak-api. somehow it looks problematic to me that oak-jcr needs to
>> deal with internal stuff (and thus any other implementation of the
>> would need to do the same).
>Right, it's a trade-off between the size of the Oak API and complexity
>of clients.
>The reason why I instinctively prefer to keep the Oak API as tight and
>simple as possible is that we'll be needing various kinds of wrappers
>like remoting, caching, virtualization or logging layers around it.
>The smaller the API is, the easier it is to create and maintain such
>wrappers. And since oak-jcr and to a lesser degree oak-http are the
>only complex direct Java clients of the Oak API that we plan to
>support, pushing more functionality to above the Oak API to avoid
>complicating it is IMO often a reasonable tradeoff.
>> wasn't it a valid alternative to really keep the exact format of that
>> internal content as implementation detail in oak-core and rather expose
>> the information using specific methods on the oak-api/spi?
>In fact, the more I think of the specific case of the proposed
>":childOrder" property and orderability of nodes, the more it seems
>that you are right - it is better to hide these details below the Oak
>API and explicitly extend the API with an orderBefore() method like
>the one in JCR. The main reason why I think we need to do this is
>access control - otherwise oak-core would in any case need to
>"understand" the :childOrder property in order to properly filter out
>the names of any child nodes that the current client doesn't have read
>access to and thus shouldn't be aware of.
>> having a comprehensive list of the affected internal content might be
>> helpful in order to decide on how to deal with it. do you know how
>> many different internal items we are taking about?
>For now the only already existing cases are the :childOrder property
>needed by the orderability feature and the search index content that
>similarly needs to be hidden from clients of the Oak API for security
>reasons. Also in this case also the Oak API provides a mechanism for
>clients to properly access such internal content.
>Potential other cases of such internal content could be locking
>details not exposed by mix:lockable, automatic node metadata (last
>modified, content hash, etc.), or conflict markers. Without looking
>deeper into how to implement such features it's hard to say how they'd
>be best handled.
>Jukka Zitting

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